Prevalence and trends of markers of hepatitis B virus, hepatitis C virus and human Immunodeficiency virus in Argentine blood donors

Blood donor records covering the period between 2004 and 2011 were analyzed. Data were collected from 27 transfusion centers throughout the country, 24 of which were public and 3 were private. In the course of the study, most (~90%) blood donors were volunteers or relatives or friends of the recipients, whereas the remaining ones were repeat volunteers, periodically subjected to screening.

Potential donors undergo a questionnaire and a physical examination performed by trained physicians. Those who are apparently healthy, are between 18-65 years old and weigh above 45 kg are qualified for donation.

The data were analyzed considering seven geographic regions: northwest (NW), northeast (NE), West, South, Center, Buenos Aires city (CABA) public and private centers, as well as the provinces that make up each region.

In addition, age and gender of 744 healthy donors randomly selected, from 2 centers where NAT assays are routinely performed, were recorded to compare the epidemiological features of NAT positive donors with those of non-reactive. The size of the healthy donor’s population was estimated by considering a confidence level of 95% and 1% of accuracy.

Serum samples were tested using third and fourth generation enzyme immune assays (EIAs) following the manufacturer’s instructions, for the presence of hepatitis B surface antigen (HBsAg), anti-Core antibody (anti-HBc), antibodies for hepatitis C and antibodies for HIV. The different centers used several methodologies, even in the same center, over the study period.

Trademarks used were, for HBsAg: PRISM HBsAg, ARCHITECT HBsAg, AxSYM HBsAg (Abbott Diagnostics, IL, USA), Murex HBsAg version 3 (Abbott Diagnostics, IL, USA) and Hepanostika HBsAg Ultra (Organon Teknika, Boxtel, The Netherlands). For anti-HBc: PRISM HBcore, ARCHITECT CORE (Abbott Diagnostics, IL, USA), Hepanostika anti-HBc Uniform (Organon Teknika, Boxtel, The Netherlands), Anti-HBc (Radim, Pomezia, Italy), Enzygnost Anti HBc (Dade Behring, IL, USA) and anti-HBc (Dia.Pro Diagnostic BioProbes, Milan, Italy). For anti-HCV: PRISM HCV, ARCHITECT anti-HCV (Abbott Diagnostics, IL, USA), HCV Version 3.0 (Ortho Clinical Diagnostics, NJ, USA), Bioelisa HCV 4.0 (Biokit, Lexington MA, USA), HCV Ab (DIA.PRO Diagnostic, Bioprobes srl, Milan, Italy) and Murex anti-HCV 4.0 (Murex Biotech Ltd., Dartford, United Kingdom) and for anti-HIV: PRISM HIV O Plus, ARCHITECT HIV Ag/Ab Combo, AxSYM HIV Ag-Ab Combination (Abbott Diagnostics, IL, USA), Murex HIV Ag-Ab Combination (Murex Biotech Ltd., Dartford, United Kingdom), HIV Ab&Ag 4th Gen (DIA.PRO Diagnostic, Bioprobes srl, Milan, Italy), VIDAS HIV Duo Ultra (Biomerieux, Marcy l’Etoile, France), GS HIV-1/HIV-2 PLUS O (Ortho Clinical Diagnostics, NJ, USA).

The HBV, HCV and HIV nucleic acids were routinely tested in two of the 27 centers using Cobas Taqscreen MPX test (ROCHE) and Procleix Ultrio test (Chiron), following the manufacturer’s instructions. Positive samples were later analyzed with Procleix HIV-1, HCV and HBV Discriminatory assays or Cobas TaqScreen MPX Test, v2.0 to determine which viral nucleic acid or combination of nucleic acids was causing the reaction.

This study was approved by the Ethics Committee of the School of Pharmacy and Biochemistry, Buenos Aires University (EXPTE. N° 732575). Interviews and blood sample collection were conducted after written consent forms had been signed. The study was performed in accordance with provisions of the Declaration of Helsinki and Good Clinical Practice guidelines.

During the 8-year study, the number of blood donors progressively increased from 352,771 in 2004 to 573,518 in 2011. The sampling in 2011 represented 1.38% of the country population, (41,660,417 inhabitants) and ranged between 0.73 and 2.10% in the different regions studied.

In 2011, the nationwide prevalence of HBsAg was 0.198 ± 0.179% (0.090-0.725%), being unevenly distributed in the different regions of the country (Table 1).

The highest prevalence rate was observed in the NW region (0.451%); particularly, among the provinces belonging to this region, Salta (0.725%) and Jujuy (0.671%) showed prevalence rates higher than the other provinces of this region (Tucuman 0.206%, Catamarca 0.319%, La Rioja 0.272% and Santiago del Estero 0.467%).

The other regions showed similar prevalence rates, ranging from 0.090 to 0.291%. However, although the rate in the NE region was within the average (0.291%), the prevalence in the province of Misiones (0.656%), belonging to this region, was significantly higher, only comparable to that in Salta and Jujuy. Finally, the prevalence of HBsAg was significantly different between CABA public centers and CABA private centers (0.181% and 0.090% respectively, p < 0.001).

The anti-HBc prevalence broadly followed the HBsAg rates, being the national prevalence 2.007 ± 2.308% (range 0.717-10.136%). The provinces with higher HBsAg rates (Salta, Jujuy and Misiones) showed high prevalence rates of anti-HBc (> 7.0%). The average ratio of anti-HBc/HBsAg was 9.87 ± 2.29, ranging from 6.074 to 12.00 in the different regions.

Along the study period, we found a slight and significant decrease at nationwide level for HBsAg prevalence from 0.356% in 2004 to 0.198% in 2011 (p < 0.0001) and for anti-HBc prevalence from 2.391% in 2004 to 2.007% in 2011 (p < 0.0001) (Table 2). This pattern was observed in four out of the seven regions studied (NW, West, Center and CABA public centers) whereas it remained steady in the other three regions (NE, South and CABA private centers) (Figure 1).

In 2011, the nationwide prevalence of anti-HCV was 0.460 ± 0.207% (0.117-1.015%), being significantly higher in the NW region (0.660%) and CABA public centers (0.641%) than in the other regions (Table 1). In particular, among the provinces belonging to the NW region, Salta (0.678%), Tucumán (0.857%) and La Rioja (1.015%) showed significantly higher prevalence rates than the other provinces of this region. The other regions showed similar prevalence rates ranging from 0.287 to 0.446%. Similarly to that observed for HBsAg, the prevalence of anti-HCV in the CABA public centers was significantly different from that in the CABA private centers, being 0.641% and 0.287% respectively (p < 0.001).

In the longitudinal study between 2004 and 2011, the nationwide level of anti-HCV showed a significant decrease from 0.721% in 2004 to 0.460% in 2011 (p < 0.0001) (Table 2). This pattern was observed in five out of seven regions studied (NE, West, Center, CABA public and CABA private); whereas it remained unchanged in the other two regions (NW and South) (Figure 1).

In 2011, the nationwide prevalence of anti-HIV was 0.190 ± 0.103% (0.012-0.376%). Overall, the prevalence by regions ranged from 0.104 to 0.247% except in CABA public centers (0.308%), where it was significantly higher than in the other regions (Table 1). In some provinces as, La Rioja (0.330%), Neuquén (0.376%) and Santa Cruz (0.338%) the prevalence was above the average.

The prevalence of anti-HIV in the public centers of CABA was significantly different from that in the private centers of CABA, being 0.308% and 0.104% respectively (p < 0.001).

Along the study period, the nationwide prevalence of anti-HIV between 2004 and 2011 was unchanged (0.208 to 0.190%; p = 0.075) (Table 2). It only showed a significant decrease in the Center (0.247 to 0.200%; p < 0.001) and a significant increase in the South (0.075 to 0.247%; p < 0.001) (Figure 1).

During 2010 and 2011, 75,200 donors were routinely tested by NAT assays in two private centers CABA; 74,838 of these were negative in serologic assays and 362 were positive in serology assays for any of transfusion-transmissible agents. Two out of 74,838 screening- negative samples were positive in NAT assays: one for HCV-RNA and the other for HIV-RNA.

On the other hand, when screening -positive samples were analyzed, HBV-DNA was detected in 41 out of 68 (60.29%) HBsAg-positive samples (Figure 2). The rate of HBV-DNA was significantly higher in those samples also reactive for anti-HBc (94.12%, 32 of 34) than in samples with HBsAg alone (24.47%, 9 of 34) (p = 8.8e-⁹). While, HCV-ARN was detected in 53 out of 216 anti-HCv positive samples (24.54%) and HIV-RNA in 52 out of 78 anti-HIV positive samples (66.67%).

Finally, when comparing healthy donors and NAT-positive samples by age, HBV-DNA positive donors were significantly older than healthy donors (46.6 ± 14.8 vs 39.5 ± 11.7, p = 0.001) (Table 3). Most of the positive samples (48.8%) come from donors over 50 years of age, while only 19.3% of healthy donors were in this age range (Figure 3). As regards HCV-RNA positive donors, age distribution was also significantly higher (50.5 ± 14.3, p < 0.0001) than that of healthy donors (Table 3); particularly, there was a clear cut of positivity frequency between donors younger than 40 years (17.0%) and those over 40 years (83.0%) (Figure 3). Finally, the age distribution of HIV-RNA-positive donors was not significantly different from that of healthy donors (37.1 ± 9.7, p = 0.168). However, the highest incidence was observed in the 30-40 age range (40.4%) (Figure 3).